Deadly explosions ripped through Belgium early Tuesday, killing at many as 23 people at the Brussels Airport and a metro station four days after authorities captured Paris attacker Salah Abdelslam.

Twin blasts at Brussels Airport killed at least 13 people, sending travelers at the international hub in Zaventem fleeing from the departure hall. The first blast shattered glass windows and scattered debris onto the sidewalks and departure lobby, where witnesses saw black plumes of smoke rising from the building.

“The entrance area of the main departure area is partly destroyed,” said Daniela Schwarzer, a traveler who witnessed the chaos.

A second explosion tore through the ceiling and ruptured water pipes, said a witness who arrived on a flight from Geneva before the incident.

About an hour after the airport blasts, another explosion shook the Maalbeek metro station, located in a Brussels district six miles from the airport. Initial reports put the death toll at 10.

“There was a really loud explosion,” Alexandre Brans told the Associated Press. “It was panic everywhere. There were a lot of people in the metro.”

The blast mangled a train car, wounding several people, whom paramedics tended to on a sidewalk outside the Lex Building. The high-rise houses an annex for the Council of the European Union about 1,000 feet from the European Commission headquarters.

The incident prompted the closure of all metro train service across the city.

The first explosions were confirmed by Brussels Airport officials, who tweeted that the building is being evacuated. The explosions went off in the departures area, scattering piles of glass onto the floor in front of a row of check-in kiosks.

“Don’t come to the airport area,” an airport official tweeted, adding that all flights have been canceled.

Several photos circulating on social media show victims with bloodied legs lying on the floor.

The blasts raised Belgium’s threat level to four, its highest degree, which is defined as “serious and imminent.”

The country has been the focus of anti-terrorism operations related to the Paris terror attacks in November 2015, when it emerged that the suspects obtained explosives and a car in the country before going to France.

Salah Abdeslam, a 26-year-old Frenchman born in Brussels believed to be the last remaining attack participant, was captured in Brussels’ Molenbeek neighborhood on Friday.

The 26-year-old’s apprehension, during which Abdeslam was shot in the leg, ended more than four months of searching for the man who was Europe’s most wanted.

Public prosecutor Francois Molins said that the suspect had wanted to blow himself up outside the French national soccer stadium the night of the attacks but changed his mind.

Belgian Foreign Minister Didier Reynders said after the arrest that Abdeslam was “ready to restart something from Brussels.”

The Zaventem airport in Brussels was rocked by at least two explosions early on Tuesday morning. The exact death toll in the attacks is unclear at this time, with estimates ranging from 13 according to the BBC to 17 as reported by Russia Today. An additional 35-40 people have been wounded.

A ceiling in the airport collapsed in the wake of the explosion, trapping dozens of travelers and complicating efforts to recover victims of the attack.

London-based Sky News has reported that at least one of the explosions was a suicide bombing.

The blasts reportedly occurred in the departures lounge and near the American Airlines desk. These reports have yet to be confirmed by an official source.

Just an hour after explosions rocked the Zaventem airport the Maalbeek metro station in Brussels was hit by an explosion.

The metro station bombing left at least 10 dead and 15 wounded, bringing the total death toll in Belgium to between 23-27.

The metro bombing took place just a few hundred yards away from the seat of the European Union government.

Travelers are being evacuated and the airport is now on lockdown. The Brussels metro system has now been shut down, leaving thousands of desperate travelers stranded at the bombed Zaventem airport.

Witnesses reported that gun shots were fired prior to the airport bombings, accompanied by shouting in Arabic.

One Israeli was wounded in the attacks. The Foreign Ministry is currently investigating whether any other Israelis were injured in the explosions.

Following the attacks, the Belgian Interior Minister has raised the country’s terror threat indicator to its highest level.

The bombings come just four days after the arrest of Salah Abdeslam in Belgium. Abdeslam is believed to have played a key role in organizing last year’s Paris terror attacks.